Abstract: The numerical analysis code for the hydrogen detonation in reactor containment or a local space in reactor building was developed using Fortran 90 language. The global-chemistry model was adopted to simulate the chemical reaction between hydrogen and air. The third-order Runge-Kutta method and the fifth-order weighted essentially non-oscillatory (WENO) scheme were adopted to hand the time-dependent term and the convection flux respectively, and the explosion of pre-mixed gas of hydrogen/air/steam in local 2-D space was simulated. The computer code was verified by comparison of predicted results and exact solutions of two cases of shock tube problems. Furthermore, this code was applied to the hydrogen detonation analysis in the compartment of BWR (boiling water reactor) building. The results show that the maximum pressure and temperature during detonation are 7.5 MPa and 3 245 K, which are caused by collisions of shock waves. It can be inferred that the hydrogen detonation may threaten containment integrity, causing the release of radioactivity.